The present invention relates to clustered turbines, particularly drag vertical axis ones. The primary use is for wind, but also other fluids such as water. This is a new way to look at drag type vertical axis turbines, as an interactive system whereby the parameters of the wind farm can be adjusted to increase the total power output. Historically, a challenge for wind turbines has been that they interfere with each other aerodynamically by creating turbulent wakes. That continues to be a problem for all horizontal axis wind turbines. Vertical axis lift wind turbines have a similar problem in terms of creating turbulence. An area of recent inquiry has been how to use those types of turbines and their resulting turbulence to advantage.
We know of no one who has applied the clustering approach to drag type turbines.
U.S. Pat. No. 8,545,168 B2 discussed wind farms of vertical axis lift turbines. The fact that U.S. Pat. No. 8,545,168 B2 referred to lift and this invention is for drag is sufficient to distinguish by structure, especially since drag blades have a leading and trailing edge and are cup-shaped. There are additional differentiations. U.S. Pat. No. 8,545,168 B2 basically concerns only rows of turbines and not the distances between them. This application is about drag only (although some method claims without prior art in U.S. Pat. No. 8,545,168 B2 do refer as well to lift turbines) so there is no overlay).
The main claim of U.S. Pat. No. 8,545,168 B2 is for rows of counter-rotating turbines. That patent is additionally not prior art because U.S. Pat. No. 8,545,168 B2 involves making certain array's of turbines that are all counter-rotating next to each other, so the arrangements in the current application are unique because counter-rotation is limited item to specific circumstances. In addition, we show later that U.S. Pat. No. 8,545,168 B2's prescription for counter-rotation would actually cause the performance of drag-type turbines to decrease throughout most of a wind farm. There is one case which we point out in which counter-rotation would be useful, with just the periphery on one side.
Vertical axis wind turbines of the predominantly drag type have a different science than that of horizontal axis. One is that wake effects differ. The turbines in this invention should be considered to be of the same size and shape, but not necessarily confined to that.